Scientists working with China’s fully superconducting Experimental Advanced Superconducting Tokamak (EAST) have reached a long-predicted state known as the “density-free regime,” where fusion plasma remains stable at densities far higher than traditional limits. The achievement marks a significant step toward solving one of fusion energy’s most persistent physical challenges. The findings were published in Science Advances on January 1.

A New High-Density Operating Strategy
The research was co-led by Prof. Ping Zhu of Huazhong University of Science and Technology and Associate Prof. Ning Yan of the Hefei Institutes of Physical Science at the Chinese Academy of Sciences. Using a newly developed high-density operating approach on EAST, the team showed that plasma density can be pushed well beyond long-accepted empirical limits without triggering the violent instabilities that typically shut down tokamak experiments.